#define _CRT_SECURE_NO_WARNINGS 1

#include "Stack.h"

void StackInit(ST* ps)
{
	assert(ps);
	ps->a = NULL;
	ps->top = 0;
	ps->capacity = 0;

}


void StackPush(ST* ps, STDataType x)
{
	assert(ps);

	if (ps->top == ps->capacity)
	{
		int newcapacity = (ps->capacity == 0 ? 4 : ps->capacity * 2);
		STDataType* tmp = realloc(ps->a, sizeof(STDataType) * newcapacity);
		if (tmp == NULL)
		{
			perror("realloc fail\n");
			exit(-1);
		}

		ps->a = tmp;
		ps->capacity = newcapacity;

	}

	ps->a[ps->top] = x;
	ps->top++;

}


void StackPop(ST* ps)
{
	assert(ps);
	assert(ps->top > 0);

	ps->top--;
}


STDataType StackTop(ST* ps)
{
	assert(ps);

	return ps->a[ps->top - 1];

}

int StackSize(ST* ps)
{
	assert(ps);
	return ps->top;

}

bool StackEmpty(ST* ps)
{
	assert(ps);
	return ps->top == 0;
}

//bool StackEmpty(ST* ps)
//{
//	assert(ps);
//	if (ps->top > 0)
//	{
//		return false;
//	}
//	else
//	{
//		return true;
//	}
//
//}


void StackDestroy(ST* ps)
{
	assert(ps);

	ps->a = NULL;
	ps->top = 0;
	ps->capacity = 0;

}